A leno thread tensioner (26, 26A, 26B) is positioned upstream, as viewed in the movement direction of the leno threads (9, 10), of a leno selvage former (1) for tensioning the leno threads especially during change-over of the leno thread. Additionally, or instead, a leno thread spreader (23) and detour member is positioned downstream of the leno selvage former for preventing intertwining of the leno threads before they are bound into the leno selvage.